1. Field of the Invention
The present invention relates to an improved probe structure, particularly to an improve probe structure, which can effectively separate the probe from the external heat source.
2. Description of the Related Art
The ear thermometer detects the infrared rays radiated by the eardrum to learn the body temperature. The eardrum is located inside the skull and near the hypothalamus—the temperature control center of the body. As the carotid fully supplies blood to the eardrum, the eardrum can promptly reflect the central temperature variation of the body. The ear temperature can be used to calculate the oral temperature and rectal temperature for clinic reference. As the ear thermometer can rapidly output temperature accurately and is easy to operate, it has been the mainstream instrument for body temperature measurement.
Generally, isolating the ear thermometer from the influence of external heat can effectively increase the accuracy thereof. Therefore, there are many designs to achieve the function. Refer to FIG. 1 for a U.S. Pat. No. 4,636,091. In the prior art, the sensor 10 is arranged inside a low-conductivity plastic sleeve 12, and a high-conductivity casing 14 separates the plastic sleeve 12 from the environment. The bottom of the sensor 10 contacts a cast piece 16 made of a high-conductivity ceramic material, and the cast piece 16 can fast conduct from the sensor 10 the heat caused by radiation. The prior-art patent uses the plastic sleeve 12 to separate the sensor 10 from the external heat conducted by the casing 14. Refer to FIG. 2. In the abovementioned design, electric capacity may simulate thermal capacity, and electric resistance may simulate thermal resistance. Thus, the path via which the external heat is conducted to the sensor 10 may be regarded as that the external heat sequentially passes through the casing 14 simulated by an electric capacitor 18, the plastic sleeve 12 simulated by an electric resistor 20, the cast piece 16 simulated by an electric capacitor 16, and a metallic sensor housing (not shown in the drawing) simulated by an electric capacitor 22.
Refer to FIG. 3 for a U.S. Pat. No. 5,018,872. In the prior art, the probe structure comprises a plastic hose 24, a metallic shelter 26 arranged inside the plastic hose 24, a sensor 28 arranged inside the metallic shelter 26, and a radiator 30 contacting the bottom of the sensor 28 to fast dissipate the heat passing through the plastic hose 24 and reaching the metallic shelter 28. Refer to FIG. 3. In the design, electric capacity may also simulate thermal capacity, and electric resistance may also simulate thermal resistance. Thus, the path via which the external heat is conducted to the sensor 28 may be regarded as that the external heat sequentially passes through the plastic hose 24 simulated by an electric resistor 32, the radiator 30 simulated by an electric capacitor 34, and the metallic shelter 26 simulated by an electric capacitor 36.
Refer to FIG. 5 for a U.S. Pat. No. 5,874,736. In the prior art, the path via which the external heat is conducted to the sensor 38 may be regarded as that the external heat sequentially passes through an electric resistance (simulating the sleeve 40), an electric capacitor (simulating the radiator 42), and an electric capacitor (simulating a flange 44 in the rear of the metallic encapsulating casing of the sensor 38). In a U.S. Pat. No. 6,743,346, the external heat is conducted to the sensor via a path of an electric resistance (a sleeve), an electric capacitor (a radiator), and an electric capacitor (a metallic encapsulating casing of the sensor).
The abovementioned prior-art patents respectively use different structures to retard the heat conducted from the external to the sensor. However, they all have the same mode-one electric resistor together with several electric capacitors. Therefore, the abovementioned prior-art patents have about identical effect in separating the sensor from the influence of external heat.
Accordingly, the present invention proposes an improved probe structure to effectively solve the problems of the conventional probe stricture.